2019-09-19 09:36:16 +02:00
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# pure sh bible
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A collection of pure POSIX `sh` alternatives to external processes
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## Table of Contents
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<!-- vim-markdown-toc GFM -->
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2019-09-19 09:56:28 +02:00
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* [STRINGS](#strings)
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* [Strip pattern from start of string](#strip-pattern-from-start-of-string)
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* [Strip pattern from end of string](#strip-pattern-from-end-of-string)
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2019-09-19 09:58:29 +02:00
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* [Trim all white-space from string and truncate spaces](#trim-all-white-space-from-string-and-truncate-spaces)
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2019-09-19 10:01:21 +02:00
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* [Check if string contains a sub-string](#check-if-string-contains-a-sub-string)
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* [Check if string starts with sub-string](#check-if-string-starts-with-sub-string)
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* [Check if string ends with sub-string](#check-if-string-ends-with-sub-string)
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2019-09-19 09:56:28 +02:00
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2019-09-19 09:36:16 +02:00
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<!-- vim-markdown-toc -->
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2019-09-19 09:56:28 +02:00
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# STRINGS
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## Strip pattern from start of string
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**Example Function:**
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```sh
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lstrip() {
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# Usage: lstrip "string" "pattern"
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printf '%s\n' "${1##$2}"
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}
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```
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**Example Usage:**
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```shell
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$ lstrip "The Quick Brown Fox" "The "
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Quick Brown Fox
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```
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## Strip pattern from end of string
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**Example Function:**
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```sh
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rstrip() {
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# Usage: rstrip "string" "pattern"
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printf '%s\n' "${1%%$2}"
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}
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```
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**Example Usage:**
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```shell
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$ rstrip "The Quick Brown Fox" " Fox"
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The Quick Brown
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```
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2019-09-19 09:58:29 +02:00
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## Trim all white-space from string and truncate spaces
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This is an alternative to `sed`, `awk`, `perl` and other tools. The
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function below works by abusing word splitting to create a new string
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without leading/trailing white-space and with truncated spaces.
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**Example Function:**
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```sh
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# shellcheck disable=SC2086,SC2048
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trim_all() {
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# Usage: trim_all " example string "
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set -f
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set -- $*
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printf '%s\n' "$*"
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set +f
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}
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```
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**Example Usage:**
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```shell
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$ trim_all " Hello, World "
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Hello, World
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$ name=" John Black is my name. "
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$ trim_all "$name"
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John Black is my name.
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```
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2019-09-19 10:01:21 +02:00
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## Check if string contains a sub-string
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**Using a case statement:**
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```shell
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case $var in
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*sub_string*)
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# Do stuff
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;;
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*sub_string2*)
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# Do more stuff
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;;
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*)
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# Else
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;;
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esac
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```
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## Check if string starts with sub-string
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**Using a case statement:**
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```shell
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case $var in
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sub_string*)
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# Do stuff
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;;
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sub_string2*)
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# Do more stuff
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;;
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*)
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# Else
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;;
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esac
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```
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## Check if string ends with sub-string
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**Using a case statement:**
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```shell
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case $var in
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*sub_string)
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# Do stuff
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;;
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*sub_string2)
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# Do more stuff
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;;
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*)
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# Else
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;;
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esac
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```
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